This invention relates to an electric-motored bicycle and more particularly, a bicycle that is provided with an auxiliary electrical power plant.
Bicycles have been proposed that incorporate electrical motors powered by rechargeable batteries for providing operator assist under certain conditions. This type of bicycle generally includes a conventional pedal operated mechanism for manual powering of the bicycle. However, an electrical motor is incorporated for adding driving assist during periods when the operator is required to output considerable energy, such as when pedaling at high speed or up steep inclines. Generally this type of mechanism includes a torque responsive switch in the pedal operated mechanism which initiates operation of the electrical motor for assist when needed.
Although such arrangements are particularly useful, they also have some disadvantages. That is, the prior art type of constructions have certain operating modes when the electrical motor interface with the driven wheel can be improved. These situations arise primarily when the rider is not riding the bicycle but is attempting to push it.
It is, therefore, a principal object of this invention to provide an improved bicycle powered both manually and electrically and wherein the electrical control for the motor is varied in response to a condition of being pushed.
For example, it is generally the practice to couple both the electrical motor and the pedal mechanism to the driven wheel through individual one-way clutches. This is done so as to ensure that each driving mode need not override or drive the other. In addition, it is generally the practice to provide in the control circuit for the electric motor a device frequently referred to as a "flywheel diode." The purpose of the flywheel diode is to provide a flow circuit for the electrical power during the time when an inductive component is generated within the motor when the motor current is cut off. As a result of this arrangement, when an operator tries to push the bicycle rearwardly, the electrical motor, which normally includes a permanent magnet and winding, will generate a reverse electrical voltage which passes through the flywheel diode circuit. As a result, there is an electrical load generated which makes it more difficult for the rider to push the bicycle in a rearward direction.
It is, therefore, a principal object of this invention to provide an arrangement for an electrically assisted bicycle to facilitate pushing of the bicycle in reverse without generating an electrical load in the motor that tends to resist this rearward pushing action.
In addition to the aforenoted problems with the prior art type of construction when the bicycle is being pushed rearwardly, the power assist, as aforenoted, is generally operative only in response to operator input to the pedals. Thus, if the operator is pushing the bicycle in a forward direction, there will be no electrical motor assist. However, there may be times when it is desirable to have the electric motor assist the operator in pushing the bicycle, for example, uphill.
It is, therefore, a further principal object of this invention to provide an improved electrically powered bicycle wherein the electric power may be employed by the operator when desired to assist in pushing the bicycle.